🚀 go-pugleaf

GCC 2.2.2 does not warn about C expressions like `1<=i<=N', which have
a different meaning than in traditional mathematics.  Here is a patch.

Fri Aug  7 22:34:20 1992  Paul Eggert  (eggert@twinsun.com)

	* c-typeck.c (parser_build_binary_op): Warn about expressions like
	`1<=i<=N'.
	* invoke.texi: Document warning.

===================================================================
RCS file: invoke.texi,v
retrieving revision 2.2.2.1
diff -c2 -r2.2.2.1 invoke.texi
*** invoke.texi	1992/08/01 03:27:09	2.2.2.1
--- invoke.texi	1992/08/07 22:22:36
***************
*** 616,619 ****
--- 616,624 ----
  
  @item
+ A comparison like @samp{x<=y<=z} appears; this is equivalent to
+ @samp{(x<=y ? 1 : 0) <= z}, which is a different interpretation than
+ ordinary mathmatics.
+ 
+ @item
  A storage-class specifier like @code{static} appears other than
  at the beginning of a declaration.  According to the C Standard,
===================================================================
RCS file: c-typeck.c,v
retrieving revision 2.2.2.3
diff -c2 -r2.2.2.3 c-typeck.c
*** c-typeck.c	1992/07/18 03:33:06	2.2.2.3
--- c-typeck.c	1992/08/07 22:34:20
***************
*** 2131,2134 ****
--- 2131,2139 ----
    class = TREE_CODE_CLASS (TREE_CODE (result));
  
+   /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
+   if (class == '<' && extra_warnings
+       && (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<'))
+     warning ("comparisons like X<=Y<=Z do not have the usual meaning");
+ 
    /* Record the code that was specified in the source,
       for the sake of warnings about confusing nesting.  */